1. Field of the Invention
The present invention relates to an image forming apparatus using a human detection technique, and particularly relates to an image forming apparatus that changes a power state by using the human detection technique. The present invention also relates to a method for controlling such image forming apparatus, and a storage medium.
2. Description of the Related Art
Conventionally, in an image forming apparatus such as a printer, a facsimile machine, and a copying machine, predetermined power generated in a power supply device is supplied to a predetermined load of the image forming apparatus. The image forming apparatus includes a power-supply control device. The power-supply control device causes a shift from a normal mode to a power-saving mode, when the image forming apparatus has not operated for a predetermined time. In the power-saving mode, power consumption is smaller than power consumption in the normal mode. However, it is necessary to maintain the normal mode for a predetermined time even after completion of an operation by a user, until the shift to the power-saving mode is completed. Therefore, unnecessary power may be consumed.
A method of trying to address this issue is to provide the image forming apparatus with a human detection unit, and adjust sensitivity of the human detection unit according to a processing execution operation of the user. Another method is to adjust a count value of a timer used for a shift to the power-saving mode, according to frequency of operating a power-saving mode release unit. There is a technique that attempts to realize compatibility between user convenience and power-consumption reduction, by using those methods (Japanese Patent Application Laid-Open No. 2012-118253).
However, in the above-described technique discussed in Japanese Patent Application Laid-Open No. 2012-118253, it is still necessary to maintain the normal mode for a predetermined time until a shift to the power-saving mode is completed, even after completion of the user operation, while adjustment of sensitivity of the human detection unit and of the count value of the timer is performed. Therefore, in this technique, unnecessary power consumption still exists.